Event DescriptionBenjamin Felzer, an assistant professor in the Department of Earth and Environmental Sciences at Lehigh University in Bethlehem, Pa., will speak on the “Effect of Climate Change, Land Use Change, Elevated Carbon Dioxide, and Air Pollution on Ecosystem Services in the U.S. Mid-Atlantic Region” on at 3:30 p.m. Wednesday April 2, in room 3131 Life Sciences Building. Felzer is an ecosystem modeler whose work focuses on coupling biogeochemistry, climate, land-use and water.According to Felzer, climate change is occurring in a context of rising levels of atmospheric carbon dioxide, atmospheric pollutants, and continued human land use change. Ecosystem services involving provisioning of food, wood, and fresh water, as well as the supporting roles of nutrient cycling and primary production, are subject to how vegetation responds to these changes to the land and atmosphere.“Climate change not only includes changes to the hydrological cycle in a context of warming, but also possibly an increase in extreme events like floods and droughts,” Felzer explained. “Vegetation response to warming is generally positive unless offset by limited moisture, while soils release more carbon to the atmosphere as a result of enhanced microbial decomposition.”Elevated atmospheric carbon dioxide levels enhance vegetation growth for C3 plants, but only up to a point. “Direct human change of the land surface, through increased urbanization, agricultural conversion or abandonment, or timber harvest, is obviously the most direct impact on vegetation,” Felzer said. “Air pollution involves surface-level ozone, which is detrimental to plant growth, and nitrogen deposition, which fertilizes plants.”Felzer’s talk will explore the role of each of these historically as well as into the 21st century. His approach involves a biogeochemical model of carbon, nitrogen and water cycling between the land and the atmosphere. The model is used to explore the role of each of these factors on forest growth, crop yield, available water, nitrogen cycling, and carbon sequestration within the Mid-Atlantic region of the United States.